The header for a message exchange that is either requesting or responding to an action. The reference(s) that are the subject of the action as well as other information related to the action are typically transmitted in a bundle in which the MessageHeader resource instance is the first resource in the bundle.

A reference to a set of rules that were followed when the resource was constructed, and which must be understood when processing the content.

Asserting this rule set restricts the content to be only understood by a limited set of trading partners. This inherently limits the usefulness of the data in the long term. However, the existing health eco-system is highly fractured, and not yet ready to define, collect, and exchange data in a generally computable sense. Wherever possible, implementers and/or specification writers should avoid using this element.

This element is labelled as a modifier because the implicit rules may provide additional knowledge about the resource that modifies it's meaning or interpretation.

An Extension

R4: MessageHeader.definition (new:canonical(MessageDefinition))

Element MessageHeader.definition has a context of MessageHeader based on following the parent source element upwards and mapping to MessageHeader. Element MessageHeader.definition has no mapping targets in FHIR STU3. Typically, this is because the element has been added (is a new element).

May be used to represent additional information that is not part of the basic definition of the resource, and that modifies the understanding of the element that contains it. Usually modifier elements provide negation or qualification. In order to make the use of extensions safe and manageable, there is a strict set of governance applied to the definition and use of extensions. Though any implementer is allowed to define an extension, there is a set of requirements that SHALL be met as part of the definition of the extension. Applications processing a resource are required to check for modifier extensions.

There can be no stigma associated with the use of extensions by any application, project, or standard - regardless of the institution or jurisdiction that uses or defines the extensions. The use of extensions is what allows the FHIR specification to retain a core level of simplicity for everyone.

Code that identifies the event this message represents and connects it with its definition. Events defined as part of the FHIR specification have the system value "http://hl7.org/fhir/message-events".

One of the message events defined as part of FHIR.

Drives the behavior associated with this message.

An Extension

R4: MessageHeader.event[x] additional types (uri) additional types from child elements (value)

Element MessageHeader.event[x] is mapped to FHIR STU3 element MessageHeader.event as SourceIsBroaderThanTarget. The mappings for MessageHeader.event[x] do not cover the following types: uri. The mappings for MessageHeader.event[x] do not cover the following types based on type expansion: value. The time of the event will be found in the focus resource. The time of the message will be found in Bundle.timestamp.

The time that the message was sent.

Allows limited detection of out-of-order and delayed transmission. Also supports audit.

The source application from which this message originated.

Allows replies, supports audit.

May be used to represent additional information that is not part of the basic definition of the element, and that modifies the understanding of the element that contains it. Usually modifier elements provide negation or qualification. In order to make the use of extensions safe and manageable, there is a strict set of governance applied to the definition and use of extensions. Though any implementer is allowed to define an extension, there is a set of requirements that SHALL be met as part of the definition of the extension. Applications processing a resource are required to check for modifier extensions.

There can be no stigma associated with the use of extensions by any application, project, or standard - regardless of the institution or jurisdiction that uses or defines the extensions. The use of extensions is what allows the FHIR specification to retain a core level of simplicity for everyone.

Identifies the routing target to send acknowledgements to.

The id may be a non-resolvable URI for systems that do not use standard network-based addresses.

Identifies where to send responses, may influence security permissions.

R4: MessageHeader.definition (new:canonical(MessageDefinition))

Element MessageHeader.definition has a context of MessageHeader based on following the parent source element upwards and mapping to MessageHeader. Element MessageHeader.definition has no mapping targets in FHIR STU3. Typically, this is because the element has been added (is a new element).

R4: MessageHeader.event[x] additional types (uri) additional types from child elements (value)

Element MessageHeader.event[x] is mapped to FHIR STU3 element MessageHeader.event as SourceIsBroaderThanTarget. The mappings for MessageHeader.event[x] do not cover the following types: uri. The mappings for MessageHeader.event[x] do not cover the following types based on type expansion: value. The time of the event will be found in the focus resource. The time of the message will be found in Bundle.timestamp.

R4: MessageHeader.destination.receiver

Element MessageHeader.destination.receiver is mapped to FHIR STU3 element MessageHeader.receiver as SourceIsBroaderThanTarget. The standard extension alternate-reference has been mapped as the representation of FHIR R4 element MessageHeader.destination.receiver with unmapped reference targets: PractitionerRole.

R4: MessageHeader.sender

Element MessageHeader.sender is mapped to FHIR STU3 element MessageHeader.sender as SourceIsBroaderThanTarget. The standard extension alternate-reference has been mapped as the representation of FHIR R4 element MessageHeader.sender with unmapped reference targets: PractitionerRole. Use case is for where a (trusted) sending system is responsible for multiple organizations, and therefore cannot differentiate based on source endpoint / authentication alone.

R4: MessageHeader.enterer additional types from child elements (display, identifier, reference, type)

Element MessageHeader.enterer is mapped to FHIR STU3 element MessageHeader.enterer as SourceIsBroaderThanTarget. The mappings for MessageHeader.enterer do not cover the following types based on type expansion: display, identifier, reference, type. The standard extension alternate-reference has been mapped as the representation of FHIR R4 element MessageHeader.enterer with unmapped reference targets: PractitionerRole. Usually only for the request but can be used in a response.

R4: MessageHeader.author additional types from child elements (display, identifier, reference, type)

Element MessageHeader.author is mapped to FHIR STU3 element MessageHeader.author as SourceIsBroaderThanTarget. The mappings for MessageHeader.author do not cover the following types based on type expansion: display, identifier, reference, type. The standard extension alternate-reference has been mapped as the representation of FHIR R4 element MessageHeader.author with unmapped reference targets: PractitionerRole. Usually only for the request but can be used in a response.

R4: MessageHeader.responsible

Element MessageHeader.responsible is mapped to FHIR STU3 element MessageHeader.responsible as SourceIsBroaderThanTarget. The standard extension alternate-reference has been mapped as the representation of FHIR R4 element MessageHeader.responsible with unmapped reference targets: PractitionerRole. Usually only for the request but can be used in a response.

The header for a message exchange that is either requesting or responding to an action. The reference(s) that are the subject of the action as well as other information related to the action are typically transmitted in a bundle in which the MessageHeader resource instance is the first resource in the bundle.

The logical id of the resource, as used in the URL for the resource. Once assigned, this value never changes.

The only time that a resource does not have an id is when it is being submitted to the server using a create operation.

The metadata about the resource. This is content that is maintained by the infrastructure. Changes to the content may not always be associated with version changes to the resource.

A reference to a set of rules that were followed when the resource was constructed, and which must be understood when processing the content.

Asserting this rule set restricts the content to be only understood by a limited set of trading partners. This inherently limits the usefulness of the data in the long term. However, the existing health eco-system is highly fractured, and not yet ready to define, collect, and exchange data in a generally computable sense. Wherever possible, implementers and/or specification writers should avoid using this element.

This element is labelled as a modifier because the implicit rules may provide additional knowledge about the resource that modifies it's meaning or interpretation.

The base language in which the resource is written.

Language is provided to support indexing and accessibility (typically, services such as text to speech use the language tag). The html language tag in the narrative applies to the narrative. The language tag on the resource may be used to specify the language of other presentations generated from the data in the resource Not all the content has to be in the base language. The Resource.language should not be assumed to apply to the narrative automatically. If a language is specified, it should it also be specified on the div element in the html (see rules in HTML5 for information about the relationship between xml:lang and the html lang attribute).

A human language.

A human-readable narrative that contains a summary of the resource, and may be used to represent the content of the resource to a human. The narrative need not encode all the structured data, but is required to contain sufficient detail to make it "clinically safe" for a human to just read the narrative. Resource definitions may define what content should be represented in the narrative to ensure clinical safety.

Contained resources do not have narrative. Resources that are not contained SHOULD have a narrative. In some cases, a resource may only have text with little or no additional discrete data (as long as all minOccurs=1 elements are satisfied). This may be necessary for data from legacy systems where information is captured as a "text blob" or where text is additionally entered raw or narrated and encoded in formation is added later.

These resources do not have an independent existence apart from the resource that contains them - they cannot be identified independently, and nor can they have their own independent transaction scope.

This should never be done when the content can be identified properly, as once identification is lost, it is extremely difficult (and context dependent) to restore it again.

An Extension

R4: MessageHeader.definition (new:canonical(MessageDefinition))

Element MessageHeader.definition has a context of MessageHeader based on following the parent source element upwards and mapping to MessageHeader. Element MessageHeader.definition has no mapping targets in FHIR STU3. Typically, this is because the element has been added (is a new element).

May be used to represent additional information that is not part of the basic definition of the resource, and that modifies the understanding of the element that contains it. Usually modifier elements provide negation or qualification. In order to make the use of extensions safe and manageable, there is a strict set of governance applied to the definition and use of extensions. Though any implementer is allowed to define an extension, there is a set of requirements that SHALL be met as part of the definition of the extension. Applications processing a resource are required to check for modifier extensions.

There can be no stigma associated with the use of extensions by any application, project, or standard - regardless of the institution or jurisdiction that uses or defines the extensions. The use of extensions is what allows the FHIR specification to retain a core level of simplicity for everyone.

Code that identifies the event this message represents and connects it with its definition. Events defined as part of the FHIR specification have the system value "http://hl7.org/fhir/message-events".

One of the message events defined as part of FHIR.

Drives the behavior associated with this message.

unique id for the element within a resource (for internal references). This may be any string value that does not contain spaces.

An Extension

R4: MessageHeader.event[x] additional types (uri) additional types from child elements (value)

Element MessageHeader.event[x] is mapped to FHIR STU3 element MessageHeader.event as SourceIsBroaderThanTarget. The mappings for MessageHeader.event[x] do not cover the following types: uri. The mappings for MessageHeader.event[x] do not cover the following types based on type expansion: value. The time of the event will be found in the focus resource. The time of the message will be found in Bundle.timestamp.

The identification of the code system that defines the meaning of the symbol in the code.

The URI may be an OID (urn:oid:...) or a UUID (urn:uuid:...). OIDs and UUIDs SHALL be references to the HL7 OID registry. Otherwise, the URI should come from HL7's list of FHIR defined special URIs or it should de-reference to some definition that establish the system clearly and unambiguously.

Need to be unambiguous about the source of the definition of the symbol.

The version of the code system which was used when choosing this code. Note that a well-maintained code system does not need the version reported, because the meaning of codes is consistent across versions. However this cannot consistently be assured. and when the meaning is not guaranteed to be consistent, the version SHOULD be exchanged.

Where the terminology does not clearly define what string should be used to identify code system versions, the recommendation is to use the date (expressed in FHIR date format) on which that version was officially published as the version date.

A symbol in syntax defined by the system. The symbol may be a predefined code or an expression in a syntax defined by the coding system (e.g. post-coordination).

Need to refer to a particular code in the system.

A representation of the meaning of the code in the system, following the rules of the system.

Need to be able to carry a human-readable meaning of the code for readers that do not know the system.

Indicates that this coding was chosen by a user directly - i.e. off a pick list of available items (codes or displays).

Amongst a set of alternatives, a directly chosen code is the most appropriate starting point for new translations. There is some ambiguity about what exactly 'directly chosen' implies, and trading partner agreement may be needed to clarify the use of this element and its consequences more completely.

This has been identified as a clinical safety criterium - that this exact system/code pair was chosen explicitly, rather than inferred by the system based on some rules or language processing.

The destination application which the message is intended for.

There SHOULD be at least one destination, but in some circumstances, the source system is unaware of any particular destination system.

Indicates where message is to be sent for routing purposes. Allows verification of "am I the intended recipient".

unique id for the element within a resource (for internal references). This may be any string value that does not contain spaces.

May be used to represent additional information that is not part of the basic definition of the element. In order to make the use of extensions safe and manageable, there is a strict set of governance applied to the definition and use of extensions. Though any implementer is allowed to define an extension, there is a set of requirements that SHALL be met as part of the definition of the extension.

There can be no stigma associated with the use of extensions by any application, project, or standard - regardless of the institution or jurisdiction that uses or defines the extensions. The use of extensions is what allows the FHIR specification to retain a core level of simplicity for everyone.

May be used to represent additional information that is not part of the basic definition of the element, and that modifies the understanding of the element that contains it. Usually modifier elements provide negation or qualification. In order to make the use of extensions safe and manageable, there is a strict set of governance applied to the definition and use of extensions. Though any implementer is allowed to define an extension, there is a set of requirements that SHALL be met as part of the definition of the extension. Applications processing a resource are required to check for modifier extensions.

There can be no stigma associated with the use of extensions by any application, project, or standard - regardless of the institution or jurisdiction that uses or defines the extensions. The use of extensions is what allows the FHIR specification to retain a core level of simplicity for everyone.

Human-readable name for the target system.

May be used for routing of response and/or to support audit.

Identifies the target end system in situations where the initial message transmission is to an intermediary system.

Supports multi-hop routing.

Indicates where the message should be routed to.

The id may be a non-resolvable URI for systems that do not use standard network-based addresses.

Identifies where to route the message.

Allows data conveyed by a message to be addressed to a particular person or department when routing to a specific application isn't sufficient.

Allows routing beyond just the application level.

unique id for the element within a resource (for internal references). This may be any string value that does not contain spaces.

An Extension

R4: MessageHeader.destination.receiver

Element MessageHeader.destination.receiver is mapped to FHIR STU3 element MessageHeader.receiver as SourceIsBroaderThanTarget. The standard extension alternate-reference has been mapped as the representation of FHIR R4 element MessageHeader.destination.receiver with unmapped reference targets: PractitionerRole.

A reference to a location at which the other resource is found. The reference may be a relative reference, in which case it is relative to the service base URL, or an absolute URL that resolves to the location where the resource is found. The reference may be version specific or not. If the reference is not to a FHIR RESTful server, then it should be assumed to be version specific. Internal fragment references (start with '#') refer to contained resources.

Using absolute URLs provides a stable scalable approach suitable for a cloud/web context, while using relative/logical references provides a flexible approach suitable for use when trading across closed eco-system boundaries. Absolute URLs do not need to point to a FHIR RESTful server, though this is the preferred approach. If the URL conforms to the structure "/[type]/[id]" then it should be assumed that the reference is to a FHIR RESTful server.

An identifier for the other resource. This is used when there is no way to reference the other resource directly, either because the entity is not available through a FHIR server, or because there is no way for the author of the resource to convert a known identifier to an actual location. There is no requirement that a Reference.identifier point to something that is actually exposed as a FHIR instance, but it SHALL point to a business concept that would be expected to be exposed as a FHIR instance, and that instance would need to be of a FHIR resource type allowed by the reference.

When an identifier is provided in place of a reference, any system processing the reference will only be able to resolve the identifier to a reference if it understands the business context in which the identifier is used. Sometimes this is global (e.g. a national identifier) but often it is not. For this reason, none of the useful mechanisms described for working with references (e.g. chaining, includes) are possible, nor should servers be expected to be able resolve the reference. Servers may accept an identifier based reference untouched, resolve it, and/or reject it - see CapabilityStatement.rest.resource.referencePolicy.

When both an identifier and a literal reference are provided, the literal reference is preferred. Applications processing the resource are allowed - but not required - to check that the identifier matches the literal reference

Applications converting a logical reference to a literal reference may choose to leave the logical reference present, or remove it.

Plain text narrative that identifies the resource in addition to the resource reference.

This is generally not the same as the Resource.text of the referenced resource. The purpose is to identify what's being referenced, not to fully describe it.

Identifies the sending system to allow the use of a trust relationship.

Use case is for where a (trusted) sending system is responsible for multiple organizations, and therefore cannot differentiate based on source endpoint / authentication alone.

Allows routing beyond just the application level.

unique id for the element within a resource (for internal references). This may be any string value that does not contain spaces.

An Extension

R4: MessageHeader.sender

Element MessageHeader.sender is mapped to FHIR STU3 element MessageHeader.sender as SourceIsBroaderThanTarget. The standard extension alternate-reference has been mapped as the representation of FHIR R4 element MessageHeader.sender with unmapped reference targets: PractitionerRole. Use case is for where a (trusted) sending system is responsible for multiple organizations, and therefore cannot differentiate based on source endpoint / authentication alone.

A reference to a location at which the other resource is found. The reference may be a relative reference, in which case it is relative to the service base URL, or an absolute URL that resolves to the location where the resource is found. The reference may be version specific or not. If the reference is not to a FHIR RESTful server, then it should be assumed to be version specific. Internal fragment references (start with '#') refer to contained resources.

Using absolute URLs provides a stable scalable approach suitable for a cloud/web context, while using relative/logical references provides a flexible approach suitable for use when trading across closed eco-system boundaries. Absolute URLs do not need to point to a FHIR RESTful server, though this is the preferred approach. If the URL conforms to the structure "/[type]/[id]" then it should be assumed that the reference is to a FHIR RESTful server.

An identifier for the other resource. This is used when there is no way to reference the other resource directly, either because the entity is not available through a FHIR server, or because there is no way for the author of the resource to convert a known identifier to an actual location. There is no requirement that a Reference.identifier point to something that is actually exposed as a FHIR instance, but it SHALL point to a business concept that would be expected to be exposed as a FHIR instance, and that instance would need to be of a FHIR resource type allowed by the reference.

When an identifier is provided in place of a reference, any system processing the reference will only be able to resolve the identifier to a reference if it understands the business context in which the identifier is used. Sometimes this is global (e.g. a national identifier) but often it is not. For this reason, none of the useful mechanisms described for working with references (e.g. chaining, includes) are possible, nor should servers be expected to be able resolve the reference. Servers may accept an identifier based reference untouched, resolve it, and/or reject it - see CapabilityStatement.rest.resource.referencePolicy.

When both an identifier and a literal reference are provided, the literal reference is preferred. Applications processing the resource are allowed - but not required - to check that the identifier matches the literal reference

Applications converting a logical reference to a literal reference may choose to leave the logical reference present, or remove it.

Plain text narrative that identifies the resource in addition to the resource reference.

This is generally not the same as the Resource.text of the referenced resource. The purpose is to identify what's being referenced, not to fully describe it.

The time that the message was sent.

Allows limited detection of out-of-order and delayed transmission. Also supports audit.

The person or device that performed the data entry leading to this message. When there is more than one candidate, pick the most proximal to the message. Can provide other enterers in extensions.

Usually only for the request, but can be used in a response.

Need to know for audit/traceback requirements and possibly for authorization.

unique id for the element within a resource (for internal references). This may be any string value that does not contain spaces.

An Extension

R4: MessageHeader.enterer additional types from child elements (display, identifier, reference, type)

Element MessageHeader.enterer is mapped to FHIR STU3 element MessageHeader.enterer as SourceIsBroaderThanTarget. The mappings for MessageHeader.enterer do not cover the following types based on type expansion: display, identifier, reference, type. The standard extension alternate-reference has been mapped as the representation of FHIR R4 element MessageHeader.enterer with unmapped reference targets: PractitionerRole. Usually only for the request but can be used in a response.

A reference to a location at which the other resource is found. The reference may be a relative reference, in which case it is relative to the service base URL, or an absolute URL that resolves to the location where the resource is found. The reference may be version specific or not. If the reference is not to a FHIR RESTful server, then it should be assumed to be version specific. Internal fragment references (start with '#') refer to contained resources.

Using absolute URLs provides a stable scalable approach suitable for a cloud/web context, while using relative/logical references provides a flexible approach suitable for use when trading across closed eco-system boundaries. Absolute URLs do not need to point to a FHIR RESTful server, though this is the preferred approach. If the URL conforms to the structure "/[type]/[id]" then it should be assumed that the reference is to a FHIR RESTful server.

An identifier for the other resource. This is used when there is no way to reference the other resource directly, either because the entity is not available through a FHIR server, or because there is no way for the author of the resource to convert a known identifier to an actual location. There is no requirement that a Reference.identifier point to something that is actually exposed as a FHIR instance, but it SHALL point to a business concept that would be expected to be exposed as a FHIR instance, and that instance would need to be of a FHIR resource type allowed by the reference.

When an identifier is provided in place of a reference, any system processing the reference will only be able to resolve the identifier to a reference if it understands the business context in which the identifier is used. Sometimes this is global (e.g. a national identifier) but often it is not. For this reason, none of the useful mechanisms described for working with references (e.g. chaining, includes) are possible, nor should servers be expected to be able resolve the reference. Servers may accept an identifier based reference untouched, resolve it, and/or reject it - see CapabilityStatement.rest.resource.referencePolicy.

When both an identifier and a literal reference are provided, the literal reference is preferred. Applications processing the resource are allowed - but not required - to check that the identifier matches the literal reference

Applications converting a logical reference to a literal reference may choose to leave the logical reference present, or remove it.

Plain text narrative that identifies the resource in addition to the resource reference.

This is generally not the same as the Resource.text of the referenced resource. The purpose is to identify what's being referenced, not to fully describe it.

The logical author of the message - the person or device that decided the described event should happen. When there is more than one candidate, pick the most proximal to the MessageHeader. Can provide other authors in extensions.

Usually only for the request, but can be used in a response.

Need to know for audit/traceback requirements and possibly for authorization.

unique id for the element within a resource (for internal references). This may be any string value that does not contain spaces.

An Extension

R4: MessageHeader.author additional types from child elements (display, identifier, reference, type)

Element MessageHeader.author is mapped to FHIR STU3 element MessageHeader.author as SourceIsBroaderThanTarget. The mappings for MessageHeader.author do not cover the following types based on type expansion: display, identifier, reference, type. The standard extension alternate-reference has been mapped as the representation of FHIR R4 element MessageHeader.author with unmapped reference targets: PractitionerRole. Usually only for the request but can be used in a response.

A reference to a location at which the other resource is found. The reference may be a relative reference, in which case it is relative to the service base URL, or an absolute URL that resolves to the location where the resource is found. The reference may be version specific or not. If the reference is not to a FHIR RESTful server, then it should be assumed to be version specific. Internal fragment references (start with '#') refer to contained resources.

Using absolute URLs provides a stable scalable approach suitable for a cloud/web context, while using relative/logical references provides a flexible approach suitable for use when trading across closed eco-system boundaries. Absolute URLs do not need to point to a FHIR RESTful server, though this is the preferred approach. If the URL conforms to the structure "/[type]/[id]" then it should be assumed that the reference is to a FHIR RESTful server.

An identifier for the other resource. This is used when there is no way to reference the other resource directly, either because the entity is not available through a FHIR server, or because there is no way for the author of the resource to convert a known identifier to an actual location. There is no requirement that a Reference.identifier point to something that is actually exposed as a FHIR instance, but it SHALL point to a business concept that would be expected to be exposed as a FHIR instance, and that instance would need to be of a FHIR resource type allowed by the reference.

When an identifier is provided in place of a reference, any system processing the reference will only be able to resolve the identifier to a reference if it understands the business context in which the identifier is used. Sometimes this is global (e.g. a national identifier) but often it is not. For this reason, none of the useful mechanisms described for working with references (e.g. chaining, includes) are possible, nor should servers be expected to be able resolve the reference. Servers may accept an identifier based reference untouched, resolve it, and/or reject it - see CapabilityStatement.rest.resource.referencePolicy.

When both an identifier and a literal reference are provided, the literal reference is preferred. Applications processing the resource are allowed - but not required - to check that the identifier matches the literal reference

Applications converting a logical reference to a literal reference may choose to leave the logical reference present, or remove it.

Plain text narrative that identifies the resource in addition to the resource reference.

This is generally not the same as the Resource.text of the referenced resource. The purpose is to identify what's being referenced, not to fully describe it.

The source application from which this message originated.

Allows replies, supports audit.

unique id for the element within a resource (for internal references). This may be any string value that does not contain spaces.

May be used to represent additional information that is not part of the basic definition of the element. In order to make the use of extensions safe and manageable, there is a strict set of governance applied to the definition and use of extensions. Though any implementer is allowed to define an extension, there is a set of requirements that SHALL be met as part of the definition of the extension.

There can be no stigma associated with the use of extensions by any application, project, or standard - regardless of the institution or jurisdiction that uses or defines the extensions. The use of extensions is what allows the FHIR specification to retain a core level of simplicity for everyone.

May be used to represent additional information that is not part of the basic definition of the element, and that modifies the understanding of the element that contains it. Usually modifier elements provide negation or qualification. In order to make the use of extensions safe and manageable, there is a strict set of governance applied to the definition and use of extensions. Though any implementer is allowed to define an extension, there is a set of requirements that SHALL be met as part of the definition of the extension. Applications processing a resource are required to check for modifier extensions.

There can be no stigma associated with the use of extensions by any application, project, or standard - regardless of the institution or jurisdiction that uses or defines the extensions. The use of extensions is what allows the FHIR specification to retain a core level of simplicity for everyone.

Human-readable name for the source system.

May be used to support audit.

May include configuration or other information useful in debugging.

Supports audit and possibly interface engine behavior.

Can convey versions of multiple systems in situations where a message passes through multiple hands.

Supports audit and possibly interface engine behavior.

An e-mail, phone, website or other contact point to use to resolve issues with message communications.

Allows escalation of technical issues.

Identifies the routing target to send acknowledgements to.

The id may be a non-resolvable URI for systems that do not use standard network-based addresses.

Identifies where to send responses, may influence security permissions.

The person or organization that accepts overall responsibility for the contents of the message. The implication is that the message event happened under the policies of the responsible party.

Usually only for the request, but can be used in a response.

Need to know for audit/traceback requirements and possibly for authorization.

unique id for the element within a resource (for internal references). This may be any string value that does not contain spaces.

An Extension

R4: MessageHeader.responsible

Element MessageHeader.responsible is mapped to FHIR STU3 element MessageHeader.responsible as SourceIsBroaderThanTarget. The standard extension alternate-reference has been mapped as the representation of FHIR R4 element MessageHeader.responsible with unmapped reference targets: PractitionerRole. Usually only for the request but can be used in a response.

A reference to a location at which the other resource is found. The reference may be a relative reference, in which case it is relative to the service base URL, or an absolute URL that resolves to the location where the resource is found. The reference may be version specific or not. If the reference is not to a FHIR RESTful server, then it should be assumed to be version specific. Internal fragment references (start with '#') refer to contained resources.

Using absolute URLs provides a stable scalable approach suitable for a cloud/web context, while using relative/logical references provides a flexible approach suitable for use when trading across closed eco-system boundaries. Absolute URLs do not need to point to a FHIR RESTful server, though this is the preferred approach. If the URL conforms to the structure "/[type]/[id]" then it should be assumed that the reference is to a FHIR RESTful server.

An identifier for the other resource. This is used when there is no way to reference the other resource directly, either because the entity is not available through a FHIR server, or because there is no way for the author of the resource to convert a known identifier to an actual location. There is no requirement that a Reference.identifier point to something that is actually exposed as a FHIR instance, but it SHALL point to a business concept that would be expected to be exposed as a FHIR instance, and that instance would need to be of a FHIR resource type allowed by the reference.

When an identifier is provided in place of a reference, any system processing the reference will only be able to resolve the identifier to a reference if it understands the business context in which the identifier is used. Sometimes this is global (e.g. a national identifier) but often it is not. For this reason, none of the useful mechanisms described for working with references (e.g. chaining, includes) are possible, nor should servers be expected to be able resolve the reference. Servers may accept an identifier based reference untouched, resolve it, and/or reject it - see CapabilityStatement.rest.resource.referencePolicy.

When both an identifier and a literal reference are provided, the literal reference is preferred. Applications processing the resource are allowed - but not required - to check that the identifier matches the literal reference

Applications converting a logical reference to a literal reference may choose to leave the logical reference present, or remove it.

Plain text narrative that identifies the resource in addition to the resource reference.

This is generally not the same as the Resource.text of the referenced resource. The purpose is to identify what's being referenced, not to fully describe it.

Coded indication of the cause for the event - indicates a reason for the occurrence of the event that is a focus of this message.

Reason for event occurrence

Need to be able to track why resources are being changed and report in the audit log/history of the resource. May affect authorization.

Information about the message that this message is a response to. Only present if this message is a response.

unique id for the element within a resource (for internal references). This may be any string value that does not contain spaces.

May be used to represent additional information that is not part of the basic definition of the element. In order to make the use of extensions safe and manageable, there is a strict set of governance applied to the definition and use of extensions. Though any implementer is allowed to define an extension, there is a set of requirements that SHALL be met as part of the definition of the extension.

There can be no stigma associated with the use of extensions by any application, project, or standard - regardless of the institution or jurisdiction that uses or defines the extensions. The use of extensions is what allows the FHIR specification to retain a core level of simplicity for everyone.

May be used to represent additional information that is not part of the basic definition of the element, and that modifies the understanding of the element that contains it. Usually modifier elements provide negation or qualification. In order to make the use of extensions safe and manageable, there is a strict set of governance applied to the definition and use of extensions. Though any implementer is allowed to define an extension, there is a set of requirements that SHALL be met as part of the definition of the extension. Applications processing a resource are required to check for modifier extensions.

There can be no stigma associated with the use of extensions by any application, project, or standard - regardless of the institution or jurisdiction that uses or defines the extensions. The use of extensions is what allows the FHIR specification to retain a core level of simplicity for everyone.

The MessageHeader.id of the message to which this message is a response.

Allows receiver to know what message is being responded to.

Code that identifies the type of response to the message - whether it was successful or not, and whether it should be resent or not.

This is a generic response to the request message. Specific data for the response will be found in MessageHeader.focus.

The kind of response to a message

Allows the sender of the acknowledge message to know if the request was successful or if action is needed.

Full details of any issues found in the message.

This SHALL be contained in the bundle. If any of the issues are errors, the response code SHALL be an error.

Allows the sender of the message to determine what the specific issues are.

The actual data of the message - a reference to the root/focus class of the event.

The data is defined where the transaction type is defined. The transaction data is always included in the bundle that is the full message. Only the root resource is specified. The resources it references should be contained in the bundle but are not also listed here. Multiple repetitions are allowed to cater for merges and other situations with multiple focal targets.

Every message event is about actual data, a single resource, that is identified in the definition of the event, and perhaps some or all linked resources.